1. Technical Field
The present invention relates to an active-matrix device, an electro-optical display device, and an electronic apparatus.
2. Related Art
For example, a liquid crystal display (LCD) panel employing an active-matrix driving system includes an active-matrix device with a plurality of pixel electrodes, switching elements corresponding to the pixel electrodes, and wirings connected to the switching elements (e.g. See JP-A-2004-6782).
In general, the active-matrix device uses a thin film transistor (TFT) as each of the switching elements. The TFT is composed of a semiconductor layer made of an amorphous silicon (a-Si) thin film or a polycrystalline silicon (p-Si) thin film. Those thin films are photoconductive, which may cause a leakage of incident light, thereby possibly reducing an off resistance of the TFT and shifting a threshold voltage of the TFT.
In order to solve the light leakage problem, it is common to provide a light-shielding layer such as a black matrix that shields light incident to the TFT. However, providing the light-shielding layer reduces an aperture ratio of the panel, thus reducing an amount of light passing through the panel.
Therefore, the active-matrix device (a backplane for an electro-optical display device) disclosed in JP-A-2004-6782 uses a mechanical switching element instead of the foregoing TFT. The mechanical switching element does not cause light leakage. Accordingly, no light-shielding layer is needed, thus increasing the aperture ratio. In addition, the mechanical switching element does not cause temperature-related characteristic fluctuations as occurring in the TFT, so that the switching element exhibits excellent switching characteristics.
In the switching element employed in the active-matrix device of the above related art, an actuator electrode is arranged so as to oppose a cantilever. Electrifying the actuator electrode generates an electrostatic attraction between the actuator electrode and the cantilever, whereby the cantilever is displaced to contact with each pixel electrode. This can establish an electrical continuity between the pixel electrode and the wiring.
In the above active-matrix device, however, the cantilever made of a metal is likely to have metal fatigue (fatigue destruction) due to a long-term use thereof, which can deteriorate switching characteristics of the switching element. Consequently, the active-matrix device of the related art is less reliable.